Conventionally, in an image forming apparatus such as a printer, copier, multi-function peripheral (MFP), facsimile, scanner and the like, or in a liquid crystal display device, solid-state image capturing element, confocal laser microscope and the like, a lens array is used. The lens array is equipped with a light-shielding film at the non-lens parts to prevent stray light. Not limited to the image display field, the application field of the lens array further includes optical communication field, optical disk field, image transmission and combination field, light measurement and light sensing field, light processing field and the like. As the lens array, a high-quality (high-resolution) lens array with no stray light is required.
A microlens array integrally formed with a light-shielding section is disclosed in Japanese Unexamined Patent Application Publication No. 2001-330709 in which a plurality of microlenses is formed on a transparent substrate, and a light-shielding film is formed with ink material between each microlens using an inkjet method.
The microlens array disclosed in Japanese Unexamined Patent Application Publication No. 2001-330709 is manufactured using a mold through an injection molding method. Next, black ink is ejected between each lens element through an inkjet method to spread the ink between each lens. Herein, the ink has moderate flowability, thus, the ink can spread naturally to the narrow parts between the lenses. The used ink may be solid ink, oil-based ink, water-based ink, uv-curable ink and electron beam curing ink.
However, in a case of solid ink, it is necessary to arrange a heating module for carrying out heating processing so that the solid ink has moderate flowability between the lenses, and therefore the resin material of the microlens array is limited. In the case of oil-based ink or water-based ink, it is necessary to evaporate and dry the solvent thereof, and the resin material of the microlens array is limited due to the drying module. Further, in the process of drying the solvent, the light-shielding material such as pigment and the like flows, which makes it difficult to form an even light-shielding film. In a case of electron beam curing ink, the size of the device is increased for the reason of safety. Thus, the ink mentioned above has an effect on the manufacture cost, and the material and the performance are restricted.
On the other hand, the uv-curable ink also shields the ultraviolet due to the characteristic of the light-shielding film of the microlens array, thus, it is difficult to obtain a sufficiently cured film, and the detailed curing method is not disclosed. That is, if the light-shielding property of the light-shielding film of the microlens array is improved, though the stray light and the like can be shielded, there is a problem that the curing energy cannot reach the depth direction of the light-shielding film during the UV curing process, and a film with a sufficient effect cannot be achieved.